Many computer applications require or accept input beyond the input of text from a keyboard. The types of input vary but the input can be broadly categorized as point and click. The pointing device couples an x-y position on the display with input from an actuator on the pointing device (although some computer keyboards have designated keys to duplicate some actuators for the pointing devices). Thus, an x-y position of a position icon on a display screen is combined with an input of some type from the actuator in order to select something such as a command or menu choice from a series of such choices, a piece of text, or a drawing element. This selection is known as a “point and click” operation. Thus, input devices used for this sort of input are often called “pointing devices”. Often the act of selection can be coupled with one of several command choices from one or more actuators on the point device. Sometimes these commands are a sequence of selection indications from an input so that a single click, double click and even a triple click can convey different requests. Sometimes maintaining pressure on an actuator is interpreted as a different command, for example a drag instead of a click. Sometimes alternative input actuators on the pointing device are used (so that a right click from an actuator typically on the right side of the pointing device is processed differently than a left click). In some cases, some input commands are relatively insensitive to the specific position of the position icon on the computer display such as in applications that allow a “right click” to bring up a menu or frequently used commands that are relevant to the current state of the application. Such a pointing device can be used to input commands into a wide range of applications including those operating on distributed computer terminal workstations, personal computers, games and amusement devices, and other equipment with need for user input.
One such printing device is the mouse, which is moved by the user's hand across a work surface such as a desktop. Some mouse pointing devices need or benefit from moving the mouse over a special mouse pad located on the user's desktop. The movement of the mouse is detected and communicated to the computer so that an indicator on the display screen moves. The position indicator can be something simple such as cursor, a cross hair or a more fanciful indicator ranging up to a cartoon character. For sake of simplicity, we shall call this symbol a position icon. With practice, the user can move the mouse to move the position icon over various choices, text, or locations so that one or more movements of the user's fingers can couple an input command with the location choice to make a request to be acted upon by the computer application.
The invention of the mouse is attributed to Doug Englebart as part of work done for NSA in the mid 1960's. While the mouse was a large improvement over other pointing devices such as light pens, the repetitive motions required to place the position icon in the desired location and the movements to couple an input command with the selected location have been linked with repetitive motion injuries to some computer users. The problems are particularly acute among users who use a mouse pointing device frequently as is the case with people who use such a device as part of their occupation. The unresolved problems from use of the mouse and alternative prior art pointing devices is discussed in more detail below.
In light of the popularity of the mouse as a pointing device since its invention in the mid-1960s, and the recurrent problems of repetitive motion injuries, there have been many attempts to improve the device to account for the interaction between the mouse or mouse alternatives and the human body. This trend has continued as interaction with computers in certain applications such as computer aided drafting or browsing the World Wide Web portion of the Internet may require many point and click operations and very few text input operations, thus increasing the importance of the mouse design in minimizing repetitive motion injuries. The improvements have refined the initial design but do not eliminate the adverse effects of repetitive use. A brief description of selected attempts to improve the mouse is included below.
U.S. Pat. No. 4,862,165 for an Ergonomically—Shaped Hand Controller issued in 1989. The '165 patent reviews the prior art designs for hand controllers or mouse devices and finds that the shape of the prior art mouse was not ergonomically compatible with the user's hand. The proposed solution is an alteration to the outer housing of the mouse which is asserted to be ergonomically shaped to minimize hand muscle fatigue even during protracted periods of continuous use.
U.S. Pat. No. 5,287,090 for a Combination Mouse and Track Ball Unit was issued in 1994. The '090 patent asserts that the combined mouse/trackball device of the '090 patent particularly reduces the onset and severity of or can prevent entirely repetitive strain injuries, and other neurological or orthopedic malfunctions such as tendonitis and tenosynovitis that are commonly related to usage of a flat and rectangular-type mouse. The '090 device may operate as a trackball, as a right handed mouse or a left handed mouse. In brief, the device had a track ball that protruded through the bottom of the device to act as an input when in mouse mode and also protruded through the face of the device distal to the arm of the user to serve as a thumb operated track ball. When operated as a mouse, the user moves the mouse to indirectly turn two slotted wheels positioned at right angles to one another to provide input to move the position icon. The '090 device uses a pair of V-shaped switch plates (best shown in '090 FIG. 5) which actuate microswitches located below the switch plates to convey as input command from the user. Thus, operation in mouse mode to supply the x-y input called for gross motion of the mouse using the various muscles in the arm to move the hand.
When the user chooses to move the '090 device to trackball mode, several “bullet switches” are caused to extend from the device to lift the mouse movement detector from the surface of the desk. The trackball mode required manipulation of the trackball with the thumb of the user.
U.S. Pat. No. 5,414,445 for an Ergonomic Pointing Device assigned to Microsoft Corporation was issued in 1995. The '445 patent asserts that by enlarging and modifying the shape of a mouse that the user's fatigue will be decreased through positioning the user's lower palm on a work surface such that the user's hand plane is supported by the pointing device and the user's fingers are placed in a neutral posture to control the keys on the device without the need to compress or reach. The '445 patent notes that every user is different in physical size and physical proportions and suggests that the solution is a one that does not force user's into a tightly defined “grip architecture”.
U.S. Pat. No. 5,530,455 for a Roller Mouse for Implementing Scrolling in Windows Applications assigned to Mouse Systems Corporation issued in 1996. The '455 patent adds a roller to the mouse on the top front of the mouse so that the roller is within finger reach of the three input control switches. The mouse is used in a conventional way to provide x-y input to move the icon on the display. Operation of the roller moves the displayed image in the y direction on the display (“scrolling”), of if the thumb is depressing a “shift” key the movement of the roller causes the displayed image to move in the x-y direction (“panning”).
U.S. Pat. No. 5,570,112 for Ergonomic Computer Mouse issued in 1996. The '112 patent teaches changing the mouse design from a hard outer housing to a soft foam rubber pad intended to support the wrist and palm of the user in comfort. The rubber pad is covered by a thin fabric material and otherwise operates as a conventional mouse.
U.S. Pat. No. 5,576,733 for Ergonomic Computer Mouse issued in 1996. The '733 patent attempts to minimize fatigue, discomfort and pain from sessions of extended mouse use by changing the orientation of the user's hand from generally parallel to the desk or work surface to a generally upright hand with the four fingers of the user's hand in extended but slightly bent positions in a generally upright stack with the thumb supported on the opposite side of the mouse.
U.S. Pat. No. 5,726,683 for Ergonomic Computer Mouse assigned to Midas Mouse International Pty issued in 1998. The '683 patent teaches a mouse with a smooth hard, curved housing that allows the mouse to be gripped with the ring and little finger on one face of the mouse opposing the thumb on the opposite face. The index and middle finger are curved over the top and front face of the mouse where the one or more buttons are located. While the applicants for the '683 patent assert that it is measurably superior to other commercial mouse products as indicated by EMG activity level studies, the mouse requires an x-y motion of the hand to effectuate an x-y input as do other prior art mice.
Other Pointing Devices
U.S. Pat. No. 5,543,590 for an Object Position Detector with Edge Motion Feature assigned to Synaptics, Incorporated issued in 1996 as one of several related patent applications arising from an application field in 1992. The '590 patent describes an input pad for receiving x-y input and tap signals as an alternative to a mouse type device. As it is a capacitance sensing system, the sensing mechanism does not require that the user actually touch the surface of the touchpad in order for the mechanism to sense the user's finger. The patent asserts that this feature can be used to reduce strain on the user. The text of the patent (such as column 27) describe the implementation of a “glide” feature whereby a user can slide the user's finger onto one of the outer edges of the pointing device to input a “glide” command to have the position icon move in the indicated direction as long as the user's finger remains in this perimeter position. Thus the touchpad effectively has an x-y input zone for translating movements of the finger tip into x-y movements of the icon on the displayed image, and several predefined “edge motion” glide input zones for the user to input an ongoing request for continued movement of the icon in any of the corresponding directions as long as the user's finger remains in the glide input zone.
U.S. Pat. No. 5,748,185 for Touchpad with Scroll and Pan Regions assigned to Stratos Product Development Group issued in 1998. The '185 patent teaches the use of a cursor control region, a scroll control region, and a pan control region, defined as separate areas in a touchpad. Movement of the contact point in the cursor control region causes movement of the cursor in the graphical user interface. Movement of a contact point in a scroll control or pan control region causes scrolling or panning respectively of the workspace in the Graphical User Interface (GUI).
U.S. Pat. No. 5,943,052 for Method and Apparatus for Scroll Bar Control assigned to Synaptics Incorporated issued in 1999. It teaches the use of a scroll zone having a central axis defined on a touchpad. The patent teaches the use of software to scroll the information in an active window owned by the operating system or software application. The software is adapted to not scroll based on finger input that is not substantially parallel to the axis of the scroll zone.
U.S. Pat. No. 6,031,518 for Ergonomic Input Device assigned to Microsoft Corporation issued in 2000. The disclosed device is like a mouse in that it is a pointing device to be placed on top of the work space and is shaped to accommodate the geometry of the hand and fingers. Unlike a mouse, it does not require x-y motion of the mouse to effectuate an x-y motion of the position icon on the display. The actuators on this device are: a track ball positioned to be manipulated by the index finger, keys positioned to be operated by the thumb, and a scrolling wheel positioned to be operated by the middle finger. As shown best in FIG. 3, the device of the '518 patent continues to place the hand wrist down on the table with fingers pivoted upward to operate the various actuators.
Thus, while there have been many incremental improvements to the mouse device as well as a search for mouse alternatives such as devices employing touchpads, there are longstanding and previously unsolved problems with prior pointing devices.
Problems Associated with Prior Art Solutions
Applicant hereby incorporates by reference the following articles and will subsequently refer back to these references as REF1 through REF7, respectively.    REF1: Repetitive Motion Disorders statistical graph based on Bureau of Labor Statistics—University of California, San Francisco and University of California, Berkeley Ergonomics Program 1999    REF2: Table 3. Number and Percent of nonfatal occupational injuries and illnesses involving days away from work involving repetitive motion by selected worker and case characteristics 1997—U.S. Department of Labor—Bureau of Labor Statistics April 1999    REF3: Computer Related Symptoms: A Major Problem For College Students page 2 of 6 statistical graph FIG. 1: Discomfort Intensity Rating For Each Body Part—Erik Peper, Ph.D. and Katherine H. Gibney Institute for Holistic Healing Studies, San Francisco State University Sep. 4, 1998    REF4: Pointing Device Summary—Pete W. Johnson, Ph.D. University of California, San Francisco and University of California, Berkeley Ergonomics Program Jul. 18, 1994    REF5: Computer Workstation Self-Audit Checklist page 3 of 4, paragraph 1—Pete W. Johnson, Ph.D. University of California, San Francisco and University of California, Berkeley Ergonomics Program Jul. 18, 1994.    REF6: Ergonomic Guidelines for Arranging a Computer Workstation—10 Tips for Users Professor Alan Hedge, Ph.D., M.Erg.S., A.F.B.Ps.S. Cornell University—Department of Design & Environmental Analysis Ergonomics Research Laboratory Feb. 6, 1999.    REF7: Hand/Wrist Basics—Ten Things You Should Know About Hand and Wrist Pain Chris Grant, Ph.D., Certified Professional Ergonomist—F-One Ergonomics Ann Arbor, Mich. September 2000
The growing occurrence of computer-related conditions such as repetitive stress injury (RSI), tendinitis, bursitis and carpal tunnel syndrome is a serious problem. If not remedied, these injuries to the hands, wrists, arms and shoulders can become permanently debilitating. According to the Bureau of Labor Statistics (BLS), repetitive motion disorders in American office workers have doubled between 1987 to 1997. (See REF1) In 1997, over 11,000 people were reported to have missed work due to computer-related ailments. (See REF2) However, the number of unreported cases and workers who endured the pain on the job is likely much higher than that figure. Unfortunately, office workers are not the only group of computer users at risk.
The growing requirements for students to use computers is also taking a toll. A recent study conducted by Dr. Erik Peper, Ph.D. of San Francisco State University indicated that 30 percent of the university's students suffer from intense hand and wrist discomfort as a result of using computers for schoolwork. (See REF3). Additionally, the BLS suspects that home computer and Internet users are at risk for similar problems, but as yet no data is available.
Public awareness of computer-related injuries is growing. This awareness is emphasized by a recent government drive to reduce RSI in the workplace, including those related to computer use. In 1996, the Occupational Safety and Health Administration (OSHA) established a standard requiring employers to minimize recurrent repetitive stress problems at work (including office work). On the state level, California has passed laws to increase employer responsibilities further, and several other states have followed suit.
It is well known that using a computer mouse causes a large proportion of the repetitive stress injuries among computer users. Public concern about mouse-related injuries has spurred a new market in ergonomically alternative pointing devices. New government pressures on employers is also fueling this market growth. As a result, Internet and retail stores are promoting a variety of “ergonomic” pointing devices. Most of these devices represent only minor variations of conventional designs, however, and are of limited benefit to computer users subject to repetitive stress injuries.
Ergonomic Problems Associated with Pointing Devices
The nation's leading experts in computer ergonomics recognize several major pointing device problems that contribute to repetitive stress disorders. Although some of these problems overlap, they can generally be attributed to eight different ergonomic factors. These eight factors include arm/wrist movement, device placement, small muscle/tendon movement, joint position, small exertions, muscle tension, body posture and localized pressure. The following subsections describe each factor as it relates to popular pointing devices.
1. Arm/Wrist Movement
Pete W. Johnson, Ph.D., of the University of California at Berkeley and the San Francisco Ergonomics Lab in Richmond has found that conventional mouse use causes shoulder pain and injury in computer users. He attributes the distress to the repetitive arm movements that slide the mouse around the mouse pad. Dr. Johnson has found that shoulder problems are reduced with the use of stationary pointing devices such as trackballs. (See REF4 at page 2)
2. Device Placement
The placement of a pointing device relative to the user is recognized as an important factor in computer ergonomics. Professor Alan Hedge, Ph.D., of Cornell University's Department of Design and Environmental Analysis Ergonomics Laboratory emphasizes the need to keep the pointing device in a comfortable, convenient location. He says it is important in the prevention of repetitive stress disorders to keep the wrist straight and the arm close to the body. (See REF6 at pages 3 and 5). Additionally, Dr. Johnson has found that repetitive stress problems are reduced when the device is operated near the centerline of the body and no higher than the keyboard. He warns, however, that many computer workstations do not provide a safe space in which to operate the device. (See REF5) Overreaching for a poorly located pointing device is a common problem among computer users, he notes. Unfortunately, nearly all mice and trackballs are desktop devices that are operated on whatever surface the work area allows. Ideally, the hands should rest easily in the lap as much as possible.
3. Small Muscle/Tendon Movement
Some devices that minimize arm and wrist movement do so at the expense of the small muscles and the flexor and extensor tendons that work the fingers. Typical trackball devices are arranged so that the thumb or forefinger (also known as index finger) must make a kicking motion to rotate the ball and send the cursor vertically across the screen. With this kicking motion, joints are repeatedly over flexed, applying undue stress and friction to tendons and joints. Dr. Johnson discourages the use of thumb-oriented trackballs for this reason. (See REF4 at page 2). Kicking also requires the greatest amount of flexor and extensor tendon travel through the carpal tunnel, which can initiate or aggrevate carpal tunnel syndrome.
4. Joint Position
Joints, muscles and tendons experience stress and fatigue when held in unnatural positions for extended periods of time. Chris Grant, Ph.D., of F-One Ergonomics in Ann Arbor, Mich., attributes many stress problems to “non-neutral” joint postures. As a solution, Dr. Grant has found it best to keep wrist and finger joints positioned near the center of travel. (See REF7 at page 2).
According to Dr. Johnson, using desktop devices such as mice and trackballs encourage undesirable wrist extension. (See REF4 at page 2) This unnatural stretch puts harmful stress on joints, tendons and the sensitive carpal tunnel. Further compounding the problem, most mice keep fingers extended well beyond their natural position. In general, any repeated, awkward reaching or bending will cause problems in the body. Additionally, Professor Hedge emphasizes the need to keep the elbow at a right angle or straighter to prevent compressing the nerves near the joint. (See REF6 at page 3). Unfortunately, most pointing devices are desktop-operated and often keep the elbow at a less desirable, acute angle.
5. Small Exertions
Dr. Grant has found that sudden, little exertions can damage small muscles and tendons and should be avoided or minimized. (See REF7 at page 2). Even the repeated force of clicking or holding mouse buttons should not be ignored. With today's graphical, mouse-oriented computing environment, injuries from excessive clicking and dragging operations have become a serious problem. To reduce soreness in fingers and tendons, Dr. Johnson recommends using a mouse that requires the least amount of activation force to clock and hold the buttons. (See REF4 at page 2).
6. Muscle Tension
Constant muscle tension in the hands, arms and shoulders is another serious contributing factor. Dr. Hedge and Dr. Grant stress the benefits of keeping limbs and shoulders as relaxed and loose as possible. (See REF6 at page 3 and REF7 at page 2). The design of many mice and trackballs encourage gripping the device to better control the cursor. For this reason, Dr. Johnson urges users to let go of the device when not navigating. (See REF6 at page 5). Any pointing device should be held lightly when in use. Ideally, the experts agree, the hand should be in a neutral, relaxed position as much as possible between and during input actions.
7. Body Posture
Good posture is the basis of ergonomic computer use, according to Professor Hedge. (See REF6 at page 3) A good sitting posture is not stiff, but balanced and relaxed. Good posture minimizes prolonged stresses in the body, especially where skeletal support muscles are involved. In practice, however, many mice and trackballs are situated to encourage the user to slump or lean forward when reaching for them.
8. Localized Pressure
Dr. Grant stresses the importance of minimizing pressures localized to small parts of the body. He especially urges users not to support their wrists or elbows on edges or smaller surfaces. He advises against trying to offset the drawbacks of desktop pointing devices by using wrist rests. (See REF7 at pages 2 and 4) Wrist rests tend to apply pressure to the soft underside of the wrist compressing nerves together with moving tendons. Such a situation can easily compound repetitive stress problems.
Ergonomic Problem Summary
In summary, computer ergonomics experts agree them mouse-user interaction needs to be improved to reduce the stresses and irritation associated with repetitive-motion injuries. A more relaxed and natural hand and wrist position, minimal motion in the arm, wrist and fingers, and minimal button activation (or “clicking”) pressure are essential properties of a truly ergonomic pointing device. Reaching should be eliminated altogether. Shoulder and arm stresses can be reduced by using a stationary pointing device that is centrally located close to the body. A lower, centralized location encourages the most beneficial body posture and reduces elbow bend and related nerve pinching. Ideally, users would sit and work with their hands relaxed and partially open in the lap.